The Macaroni penguin (scientific name:Eudyptes chrysolophus) is is one of seventeen species of flightless birds in the family of penguins. It is one of six "Crested Penguins" in the genus Eudyptes which also includes the: Rockhopper, Fiordland crested, Snares crested, Royal and Big-crested penguins.

Like all penguins, the Macaroni penguin is characterized by its erect posture, stiff wings (flippers), excellent swimming ability, awkward movement out of water, and coloring. The black back and white front anatomy make penguins difficult to see when swimming, blending against the sea from above and the sky from below.

Physical Description

This large crested penguin is similar in appearance to other members of the genus Eudyptes. The Macaroni penguin is, however, larger than all other species except the royal penguin (E. schlegeli). Adult Macaroni penguins have golden-yellow plume-like feathers that arise from a central patch on the forehead, extending back along the crown and drooping down behind the eye. The head, chin, throat and upper-parts are black; the underparts are white and the flippers are black on the upper surface but mainly white below. The large bill is orange-brown; the eyes are red and there is a patch of bare pink skin from the base of the bill to the eye. The legs and feet of the Macaroni penguins are pink. Males and females are similar in appearance, but males tend to be slightly larger. Immature birds lack the head plumes or have a few sparse yellow feathers on the forehead; their bills are smaller than those of adults and are brownish-black in color; the chin and throat are dark gray.

Diagnostic Description: The Macaroni penguin is a medium-sized bird that stands about 71 centimeters tall and weighs between five to six kilograms. Females are usually smaller than males. Otherwise males and females appear the same (monomorphic). They have orange, yellow, and black crests that join on the top of the head. This penguin has a red bill, and the chin, face and under the throat have solid black feathers.

Reproduction

Macaroni penguins usually breed in the sub-Atlantic. Birds return to the breeding colonies each year in October and November, with males arriving before the females. Macaroni penguins may assemble by the millions in their massive rookeries and can be detected by smell as far as five to six miles offshore.

Macaroni penguins are monogamous and pair-bonds are long-lasting. Each year the pair reunites at the same nest location, recognizing each other by their calls. Pairs often perform a display known as the ecstatic display in which their heads swing from side to side.

Individuals often have to walk hundreds of meters over screes to reach their nest site. Macaroni penguin nests are made from scrapes found in mud, typically lined with small rocks or gravel among rocks. In some cases, it may be made on a patch of grass and lined with grass shoots.

Two eggs are laid; the second egg is practically always larger than the first, and is usually the only successful egg per nest. If both eggs are lost, the pair is unable to produce a replacement brood. Incubation is shared by both parents in long shifts. Incubation takes 33 to 37 days and is shared by the parents in three main shifts. The first shift lasts for eight to twelve days and is shared by the male and female. The second shift (twelve to fourteen days) is carried out by the female and the final shift (nine to eleven days) by the male. During each shift, the non-incubating bird goes to forage at sea during the day.

The newly hatched chicks are helpless, and for the first 23 to 25 days they are guarded and brooded by the male while the female forages and feeds the chicks each day by regurgitating food. After this period, the chicks have developed their first plumage, which allows them to regulate their own temperature and so they can leave the nest. They cluster into small creches for protection; at this stage, both parents are able to forage. Most chicks will have fledged at 60 to 70 days of age, at which point they have developed waterproof plumage. They do not start to breed until five years of age in females and six in males.

After the chicks leave the breeding colonies, the adults feed at sea for around three weeks before their annual molt. During the molt they are unable to forage, as their plumage is not watertight. After the 25-day molt the adults leave the colonies to spend the winter at sea.

Behavior

Macaroni penguins live in large colonies of up to 2.5 million birds, mostly in breeding pairs. Macaroni colonies are found on rocky cliffs and hillsides. Unlike birds of flight, whose bones are hollow to allow for flight, penguins have solid bones to enable deeper dives. The weight of their bones also allows them to remain under water for long periods of time. They typically surface after two or three minutes to breathe. As they swim, Macaroni penguins use their webbed feet to steer, with the help of their tails, which serve as a rudder.

Although very near-sighted on land, penguins have exceptional vision in the water. Their eyes, like the many sea animals, are attuned to the colors of the sea. This excellent vision is needed to avoid predation by leopard seals and killer whales, which are their primary predators in the ocean. On land their main predator is the skua (a large bird) which snatches penguin's chicks from nests. The penguin communicates by complex ritual behaviors such as head and flipper waving, calling, bowing, gesturing and preening. Courtship and mating rituals include so called "ecstatic displays" where a bird, typically an unattached male, pumps his chest several times with his head stretched upwards and with flippers stretched outwards, projects a harsh loud braying sound. This can result in a mass trumpeting by other males, which is believed to help synchronize the breeding cycle.

The Macaroni penguin is mainly active during the day. Very little is known of the species outside of the breeding season. Most studies have been carried out on breeding birds. They feed mainly on krill (shrimp-like crustaceans), although in some areas, fish become an increasingly important food source as the breeding season progresses. It has been estimated that Macaroni penguins alone consume four million tons of krill each year. In some populations, dives typically take the form of a V-shape, reaching depths of 48 m, although in other populations, the dive profiles were more complex.

Distribution

The Macaroni penguin has a circumpolar range. It breeds at 50 known sites on sub-Antarctic islands in the South Atlantic and southern Indian Oceans, with one breeding site on the Antarctic Peninsula. Main breeding populations are located on the islands of Crozet, Heard, McDonald, Keruguelenand South Georgia. In twelve years, study populations on South Georgia have decreased by 65% and it is thought that the overall population on South Georgia has declined by 50% in the last 20 years. Most of the world population of this penguin has declined by at least 20% in the last 36 years (equivalent to three generations), but surveys are required to confirm the status of the species. The range of the Macaroni penguin outside of the breeding season is unknown, although it is thought that it stays in Antarctic waters.

The Macaroni penguin is found on the edge of Antarctica and Sub-Antarctic islands south of the Americas and Africa. Large populations of this penguin can also be found in Chile, the Falkland Islands, South Georgia and the South Sandwich Islands, South Shetland Islands, Crozet Islands, Kerguelen Islands, and McDonald Islands.

Habitat

Breeding colonies are situated on rocky slopes or level ground, usually in areas lacking vegetation, although some nests are located amongst tussock grass (4). Little is known of this species outside of the breeding season, but it is believed that it is pelagic, spending all of its time at sea.

Predation

In undisturbed colonies, predation is relatively low. Eggs (mainly deserted ones) are predated upon by skuas, sheathbills, and kelp gulls while weakened chicks, or those separated from the creche are taken by skuas and giant petrels. Whilst at sea, adult Macaroni penguins are preyed upon by leopard seals.

As are most penguins, Macaroni penguins are counter-shaded in the water, making them difficult to see. They use their agile swimming abilities, vision, and association with other Macaroni penguins to be vigilant to predators and avoid capture in the water.

Food Habits

Macaroni penguins live almost entirely on krill (Euphasiidae) supplemented with up to five percent squid. They also eat some fish and amphipod crustaceans (Amphipoda). Macaroni penguins fast for up to forty days during the breeding season.

Conservation Status

Macaroni penguin population status is stable and increasing. They are among the most numerous penguin species in the world with a population of approximately nine million.

They are vulnerable to changes in the environment such as those due to water pollution and overfishing. Humans are the biggest threat to these penguins due to the overfishing of krill and other small invertebrates that they feed on.

Although population numbers of Macaroni penguins are high, the decline of the overall population in the last 30 years have resulted in the classification of the species as globally Vulnerable by the IUCN Red List of Threatened Species. Long-term monitoring programs are underway at a number of breeding colonies and many of the islands that support breeding populations of this penguin are protected reserves. The islands of Heard and McDonald are World Heritage Sites. If the suite of threats facing the Macaroni penguin continue unabated, it seems likely that the population declines will continue.

Threats

Many penguin species of the Southern Oceans Ecosystem share a common set of factors that are causing population reductions. Introduced predators such as cats and rats are a great problem for breeding birds on a number of islands, including South Georgia. Overfishing is a very serious factor, in particular the harvesting of krill, the main food source of the Macaroni penguin. Further pressures include oil spills and increasing tourism, as well as potential climate change, particularly as penguins are extremely sensitive to changes in sea temperature and ocean currents and the consequent decrease in prey availability

Economic Importance for Humans

Macaroni penguins live in large colonies and they represent a large potential food resource, but their economic importance is minor or insignificant to humans. Whalers and seal hunters of the nineteenth century visited some penguin colonies for meat and eggs, and there once was a penguin oil industry which took large numbers of birds but by the early 20th century, this was no longer profitable. There are no known adverse effects of Macaroni penguins on humans.